Railway-traffic-controlling apparatus



L. O. GRONDAHL RAILWAY TRAFFIC CONTROLLING APPARATUS 2 Sheets-Sheet 1 Filed Dec. 7, 1925 Fatented .lnne 2, 1925.

UNITED STATE Application filed December 7 To all whom it may conbem:

Be it known that I, LABS O. GRONDAHL, a citizen of the. United States, residing at Pittsburgh, in the county of Alleghen and State of Pennsylvania, have invente certain new and useful Improvements in Railway-Traflic-Controlling Apparatus, of which the following is a specification.

My invention relates to railway traihc controlling apparatus. 1 will describe several forms of trafiic controlling apparatus embodying my invention. and will then point out the novel fea tures thereof in claims.

In the accompanying drawings, Fig. 1 is a diagrammatic view showing one form of trackway apparatus suitable for controlling train carried governing means embodying mv invention. Fig. 2 shows a modified form 2% I the trackwey apparatus shown in Fig. 1. s. 3 and i are views showing two forms or train carried governing means each suitable for cooperation. with the trackway apparatus illustrated in Fig. 1. Fig. 5 is a View showing an arrangementpr train carried governing means suitable for cooperation with the trackway apparatus shown in Fig. 2. Fig. 8 is a view showing my invention applied to the control of the trackway signal.

Similar reference characters refer to siniilar parts in each of the several views.

Referring first to Fig. 1, the reference characters 1 and 1" designate the track rails of a stretch of railway track over which trafi'ic normally moves in the direction in dicated by the arrow. These rails are divided, loy means of insulated joints 2., into a plurality of track sections. of which one only, section AB, is shown in the drawing. Located adjacent the entrance end of the section nest in advance of section A-B is a three position signal'S controlled by means not shown in the drawing. It is sufiicient to state that when the corresponding section is occupied, the signal indicates stop; when the corresponding section is unoccupied and the next section in advance is occupied, the signal indicates caution; and when the corresponding section and the next section in advance are both unoccupied the signal indicates proceed. Means are provided for supplying section AB with alternating track circuit currents of difierent frequeno. encnnnnn, or rrr'rsnonenr, names is swrssvenn, rnnnsrn ensirn, oonronnrrcrr apparatus here shown comprises two HI YLVAIIIA, ASSIGNGEZ TO THE'UZEHGTS' moraine arranarns.

7, ices. semi at. sienna.

tuhe type. "A. track transformer T is located I adjacent the exit end oi'section A-lB, and

has its secondary 3 constantly connected with the rails of the section. The primary i of this track transformer is provided with a circuit which passes from generator iii, through wire 7, contact tl--9 operated by signal S, wire 10, primary winding 4: of transformer T, and wire'll hack to gen erator G. This circuit is closed only when signal S indicates caution or proceed AL second track transformer T has its 'secondary winding 5 connected across therzails at an intermediate point al in the section and is supplied with energy over a circuit which starts with generator H and passes through wire 12, contact 13-14- operated by signal 8 wire 15.; primary winding 6 of transformer T, and wire 16 haclr to gen erator ll. This circuit is closedonly when signal S indicates stop. it follows that sec-;..e

tion A-l3 is supplied with track circuit... current of one :trequency at point B by transformer T when signal S indicates proceed or cautio and with. track circuit cnrrent of a nt frequency point J hy transformer T when signal indicates stop. Referring now to the train carried netizalole cores 1? and 17* mounted tr versely to the two track rails l and l and in inductive relation therewith. These two cores are carried in front of the-forward axle 18 of the train. The cores 1? and. 17? are provided with two windings 19 and 19 respectively so connected that the voltages, induced therein hy currents flowing in op posite directions in the two track rails at any instant are additive. The two cores 1'? and 17 with their associated windings 19 and 19 It shall collectively term the pickup coil. This pick-up coil supplies energy to the primary 20 or a transformer K, and as here shown, suitable amplifying apparatus, is interposed hetween the two. As sociated with secondary winding 21 of transformer K is a hot wire relay M, and asso-v ciated with secondary 23 of transformer K is a similarhot wire relay N. Each of the hot wire relays M and N comprises an operating wire 24 and a contact finger 25 operated thereby. When wire 24 is cold, the Wire contracts and opens contact 2525, and when the wire 24 is heated, as by the passage of an electric'current, the resulting increase in the length of the wire allows the associated contact 2525 to close. The operating wire 24 of relay M is connected across secondary 2]. of transformer K and this circuit is tuned by means of a seriescondenser 21*, to resonance at the frequency of the current supplied by generator G. In a similar manner operating wire 24 of relay N is connected with secondary 23 of transformer K and this circuit is tuned, by means of series condenser 23, to resonance at the frequency of the current delivered by genrator H.

There are also provided on the train three indicators 26, 27 and 28 here shown as electric lamps and adapted when lighted to indicate proceed, caution, or stop, respectively.

The circuit for stop lamp 28 passes from a battery 29, through wire 30, resistance 31, wires 32 and 33, lamp 28, and wire 34 back to battery 29. This circuit is closed at all times. Caution lamp 27 is provided with. a circuit which passes from a battery 35, through wire 36, resistance 31, wires 32 and 41, lamp 27, Wire 42, contact 25-25 of hot wire relay N, and wire 40 back to battery 35. This circuit is closed only when current is flowing through operating wire 24 of relay N. Current is supplied to the proceed lamp 26 over a circuit which passes from battery 35, through wire 36, resistance 31, wire 37, lamp 26, wire 38, contact 25--25 of relay M, and wires 39 and 40 back to battery 35. This circuit is closed only when current is flowing in the operating wire 24 of relay M.

The parts are so proportioned and adjusted that when hot wire relays M and N are both de-energized current flows from battery 29 and energizes the stop lamp 28.

' If however. the circuit is closed for either of lamps 26 or 27, the voltage drop caused in resistance 31 by the passage therethrongh of current from battery 35 is equal in magnitude and opposite in direction to the electromotive force supplied by battery 29 and hence neutralizes this latter electromotive force. Under these conditions lamp 28 is extinguished.

In explaining the operation of the apparatus as awhole I will first assume that signal S in Fig; 1 is at proceed or caution. Track circuit current is therefore supplied to section A-B from generator G. If a train equipped with the apparatus shown in Fig. S'enters the section, the current which will be induced in the track coil, will be amplified and supplied to the primary 20 of transformer K. Since the circuit including secondary 21 of transformer K is tuned to resonance at the frequency of this current, there will flow in operative wire 24 of relay M a current of sufficient magnitude to close contact 25-25"- of this relay. As a result; lamp 536 will be energized. thus indicating proceed. and lamp 28 will be extinguished. This condition will continue as the train proceeds through section AB.

I will next assume that signal S is at stop and that a train enters section A-B as before. The movement of signal S to stop disconnected generator G from transformer T and connected generator H with transformer T. The train is therefore supplied with energy at the frequency of generator H be tween point A and J. Since the circuit including secondary 23 of transformer K is tuned to resonance at the frequency of generator H it follows that relay N will be energized while relay M will, of course, be de-energized. Current will therefore flow through the circuit for lamp 27 which will then be lighted to indicate caution, and the resulting voltage drop across resistance 3i will cause lamp 28 to be extinguished. As the train passes point J however, current is shunted away from the pick-up coil by the wheels and axles in rear of the coil and energy is no longer supplied to transformer K. Both relays M and N are therefore deenergized, lamps 26 and 27 are de-energized, and lamp 28 islighted, thus indicating stop. A similar condition will result if the train is in an occupied section since the effect of the wheels and axles of the train ahead is to shunt the track circuit current from the picleup coil and result in a stop indication.

Referring now to Fig. 4, only a portion.

of the apparatus is here shown, it being understood that the primar former K is connected, as in ig. 3, withthe pick-up coil. The apparatus of Fig. 4 is in all respects similar to that shown in Fig. 2 except that the batteries 35 and 29 are replaced in Fig. 4 by sources of alternating current such as the secondaries 44 and 45, respectively of a transformer D. The primary 43 of this transformer is constantly supplied with alternating current from a source notshown in the drawing. The two transformer secondaries 44 and 43 are so connected that thevoltage drop through resistance 31 at any instant when either relay M or N is closed, is equal to, and of the opposite instantaneous relative polarity from the electromotive force of winding 45. The operation of the apparatus will be readily understood from the foregoing without.

further explanation.

In the modified form of trackway apparatus shown in Fig. 2. when signal S is at proceed or caution the circuit for transform er T is closed from one terminal of generator G, through wire 48, generator H, Wire 47,

20 of transcontact 8-9 operated by signal S, wire 4-6, primary 4 of transformer T, and wire 49 hack to generator G. When this circuit is closed section A-B is supplied at point B simultaneously with currents of two frequencies, that is, with one current of the frequency of generator G and with a sec ond current of the frequency of the generator H. /Vhen signal S is at stop, a circuit is closed over which energy flows from generator H. through wires 47 and Contact 14-13 operated by signal 8, wire 51. primary 6 of transformer T and wires 50 and 48 back to generator H. When this circuit is closed current of one frequency only, the frequency of generator H), is supplied to section A-B at point J.

One form of train carried apparatus for co-operation with the trackway apparatus of Fig. 2 is shown in Fig. 5. In this View the relays M and N are controlled in the same manner'as before but the energy for operating the various indicators is now supplied by a transformer P, the primary 53 of which is constantly supplied with alternating current from a source not shown in the drawing.

The proceed indicator 26 is controlled by a relay E over the following circuit: from secondary 58 of transformer P. through wire 90. lamp 26, wire 89. front contact 89 of relay l5, and Wire 87 back to transformer secondary 58. This circuit is closed only when relay E is energized under which conclition a proceed indication is received aboard the train. Relay E is constantly connected with the secondary winding 61 of a transformer L. having two primary windings 59 and 60. The caution lamp 27 is constantly connected with the secondary 6d of a transformer i provided with two primaries 62 and 63. The stop lamp 28 is controlled in part, as shall appear hereinafter, by two transformers R and R.

When relay M is energized a circuit is closed over which current flows from winding 56 ot' transformer P. through wire 72, contact of relay'M. wire 73. primary of transformer L. wire 74. primary 62 of transformer F, wire 75. primary 67 of transformer R. and wire 76. back to second ary 56 or" transformer P. In a similar mannor the energization of relay Fl closes a circuit over which current flows from secondary 57 of transformer P. through wire 80, primary 65 of transformer R. wire 79, winding 63 of transformer F. wire 7 8, primary 60 of transformer L, wire 7'7. contact 25-25 of relay N. and wire? 2 hack to secondary 57 of transformer P. It will be seen that when relays l d and N are both energized at the same time, the currents in primaries 59 and 50 or". transformer L at any instant flow in the same directionvwhereas the currents in windings 62 and 63 of transformer F at any and wires 82 and instant flow in opposite directions. lt follows that when either relay hi or N is encrgized and the other is deenergized a current is induced in the secondary 64c of transformer F which lights lamp 2'7, but that when both these relays are energized simultaneously the magnetic fields due to currents in the primaries of transformer F tend to neutralize each other and'hence lamp 2? is (ls-energized. T he relay E however. is so designed that when only one of the primaries 59 or 60 of transformer L is energized the energy induced in winding 61 of this transformer is not sufficient to energize the relay. li both windings and 60 are simultaneous 1y energized. as by energization of both relays M and If, the e ect of these windings is additive and relay F then becomes energized and completes the circuit for lamp 26. which then becomes lighted.

The stop lamp 28 constantly connected with secondary 5: of transformer P, the cirformer P. Two relays 0 and Q are constant I ly connected with the secondary windings 6S and 66 of transformers R and Rrespectiyely. It is plain that when relay N is energized, the current flowing through primary of transformer it, as explained hereinliefore, will cause relay Q to become energized and a circuit will he closed over which current flows from secondary 54 of transformer P through wire 71, resistance 31, wires 86 and 85, front contact 83 of relay Q, i 81 back to secondary 5d of transformer F, iii branch is provided for this circuit which branch passes from wire through front contact 8d of relay G and wire 81 bac to secondary of transformer P. will appear "from the drawing when relay M is energized. It is therefore plain that when relays M and N are both ole-energized relays O and Q will both he ole-energized and stop lamp 26 will he lighted, out that when either or both of relays M and N are energized current will flow from secondary 54 of transformer P through resistance 81. The parts are so proportioned that the voltage drop thus produced in this resistance at any instant is equal in magnitudeand opposite direction to the electromotiye force of secondary 55 of transformer P and lamp 26 is therefore extinguished.

I will now assume that signal S or Fig. is at caution or proceed, and that a. train equipped with the apparatus shown in Fig.

ielay u is arranged to he energized, as

. I .H, through wire 94, back contact 91-92-of relay W, wire 95, primary 4 of transformer a caution indicatiom'lamp 27 being ener 1 If the "train now enters the stretch at A, transformer Kwill be suppliedwit gizin relay which in turn lights lamp 26., llnder these conditions lamp 27 is extinguished and relays O and Q are both energized thus causinglamp 28 to be de' energized, 1

I will next assume that signal S is. at stop. oint alternating current of one frequency only .from generator H. Since the circuit including the operating wire 24 of relay N is tuned to resonance at this frequency relay N becomes energized but relay M does not.

.usual form. The three indicator lamps 28, 27 and 26 are here shown in a trackway sig- Lamp 26 is therefore extinguishedby thede-energization of relay E. Lamp 2": is lighted however, thus indicating caution,

and theener ization of relay Q causes lam 28 to be extinguished even though relay is de-energized. As the train passes point J, the su ply of alternating current to transformer is-interrupted andrelays M and N are bothdeenergized. Lamps 26 and 27 are therefore both de energized, relays O and Q are both tie-energized, and lamp28 is lighted togiv'e a stop indication.

The train carried apparatus illustrated in any of the views may be readily modified for use in connection with trackway signals, the

apparatus shownin Fig. "6 illustrating the governing apparatus of Fig. 3 ap lied to the control of a trackway signal of the nal C of the usual form and are controlled inthe manner already described by trans former K. The primary 20 of this transformer is connected, through suitable amplifying apparatus with the rails 1 and 1 r of the section A--B.' A track relay W is connected with the rails of the section to the right of B. When this relay is energized a circuit is closed-over which current of one -frequency flows from generator G through wire 98. front-contact 91-92 of track relay W, wire '95, primary 4 of transformer T, and wire 96 back to generator G.-

Current of one frequency is thus supplied to the apparatus at point A, and relay M, becoming energized lights lamp-26 to indicate proceed. Under these conditions lamps 27- and 28 are extinguished.

In a similar manner when relay W is deenergized as by the presence of atrain in the section to the right of B, current of a difierent frequency flows from the generator T and wires 96' and 97 back to generator H. Current is then supplied .to section A--B by generator H and signal C displays gized and lamps 26 and 28 being extinguished- If section A--B is occupied by a train,

track circuit-current will be shunted away irorn primary 20 of transformer K im-{f spectivc of trafiic conditions in advance ofsection A--B, and relays M'and N both being de-energized, lamps 26 and 27'willboth -be de-energ'ized and lamp 28 will be ener:

gized and signal C, will display a stop indication. i

Although Ichave herein shown and described only a'fewforms of apparatus embodying my invention, it is understood that various changes and modifications may be made therein within the. scope of the ap-' pended claims without departingfrom the spirit and scope of my invention.

Having thus described my invention, what I claim is:

1. In a railway tratficcontrollin system,

hot wire relays responsive to tra c conditions, a plurality of indicators controlled by such relays, means for constantly applying an electromotive force to one said indicator, and means for neutralizing said electromm tive force when ,any one of the remaining indicators is energized.

2. In combination, .av stretch of railway track,-an indicator; a circuit for. said indicator including a resistance, a source of electromotive force, and means responsive to traffic conditions in said stretch; a second indicator, and a circuit for said second indicator including said resistance and a second source of eiectromotive force so connected that the voltage dro in said resistance due to current flowing t erethrough when said first circuit is closed is equal and o posite to the electromotive force of sai second source.

3. In combination, a stretch of railway track, means for supplying said stretch with alternating current of one frequency or another depending on traffic cond1tions,- two indicators, means for energizing one indicator or the other in accordance with the frequency of the current sup lied to said stretch, a third indicator, a circuit for said third indicator including a source of electromotive force, and means for neutrahzin said electromotive force when either of sai first two'indicators is energized.

4. In combination, a "stretch of railwa track, a transformer having a primary win ing and two secondary windings,-means for third indicator, and means for energizingsaid third indicator only when said first dicator and said second indicator are both (fie-energized.

5. In combination, a stretch of railway track, a first contact and a second contact controlled in accordance with traffic conditions in said stretch, a first indicator; a circuit for said indicator including a source of energy, a resistance, and said first contact: a second indicator; a circuit for said second indicator including said source, said resistance and said second contact; a third indicator. and'a circuit for said third indicator including said resistance and a second source of energy.

6. In combination, a stretch of railway track, a first contact and a second contact controlled in accordance with trafiic conditions in said stretch, a first indicator, a circuit for said indicator including a battery, a resistance, and said first contact; a second indicator; a circuit for said second indicator 'including said resistance, said battery, and said second contract; a third indicator, and a circuit for said third indicator including a secondbattery and said resistance.

7. In combination, a stretch of railway track, a first contact and a second contact controlled in accordance with traffic conditions in said stretch, a first indicator; 2. circuit for said indicator including a source of alternating current, a resistance and said first contact; a second indicator; a circuit for said indicator including said source, said battery and second contact, a third in dica-tor; and a circuit for said third indicator including a second source of alternating current and said resistance.

8. In combination, two hot wire relays, means for selectively energizing said relays, two indicators one controlled by each said relay, and a third indicator arranged to be energized only when said first two indicators are deenergized.

9. In combination,'a transformer, means for at times supplying the primary of said transformer with alternating current, a secstantly ondary on said transformer connected with the operating wires ofa hot wire relay and tuned to resonance at the frequency of said current, a contact controlled by said Wire, an indicator controlled by said contact, and a second indicator arranged to be de-energizeg only when said first indicator is energize A 10. In combination, two relays adapted to be selectively energized, an indicator conconnected with a source of energy, a second and a third indicator, means for energizing said second indicator when either of said relays is energized, means for ener-' gizing said third indicator when both said relays are energized, and gizing said first indicator when either or both of said two relays are energized.

11. In combination, two circuits tuned to means for'de-ener-- resonance at different frequencies, means controlled by trafiic conditions for at times supplying each such circuit with current of its resonant frequency, a transformer, means controlled by one said circuit for supplying alternating current of one relative polarity to one winding of said transformer, means controlled by the remaining said circuit for supplying alternating currentof the other relative polarity to a second winding on said transformer, an indicator. and a third winding on said transformer for controlling said indicator.

12. In combination, two circuits tuned to resonance at different frequencies, a trans former, means controlled by one said circuit for supplying alternating current to one winding of said transformer. means con trolled by the remaining said circuit for supplying alternating current to a secondwinding on said transformer, an indicator, and a third winding on said transformer for controlling said indicator.

13. In combination, two circuits tuned to resonance at different frequencies, a transformer, means controlled by one said circuit for supplying alternating current of one relative polarity to one Winding of said transformer. means controlled by the remaining said circuit for supplying alternating current of the same relative polarity to a second. winding indicator, and a third winding on said transformer for controlling said indicator.

14. In combination, two circuits tuned to resonance at different frequencies, a transformer, means controlled by one said circuit for supplying alternating current to one Winding of said transformer, means con-- trolled by the remaining said circuit for supplying alternating current to a second winding on said transformer, an indicator, and a third winding on saidtransformer arranged to energize said indicator only when said first winding and said second winding are both supplied with alternating current.

15. In combination, two circuits tuned to resonance at different frequencies, a transformer, means controlled by one said circiiit for supplying alternating current of onerelative polarity to one winding" of said transformer, means controlled by the relying alternatmaining said circuit for supp ing current to a second winding on said transformer, a third winding on said transformer, and a relay controlled winding for controlling said indicator.

16. In combination, two circuits tuned to resonance at different frequencies, a transformer, means controlled by one said circuit for supplying alternating current of one relative polarity to one winding of said transformer, means controlled by the remaining said circuit for supplying alternating current to a second winding on said on said transformer, an

by said third I circuit for supplying alternating current to a winding of a corresponding one of said 7 transformers, an indicator constantly connected with a source of energy, and means for ole-energizing said indicator when alternating current is being supplied to either-or both of said transformers.

'18. In combination, two circuits tuned to resonance at different frequencies, two

transformers, means controlled by each said tuned circuit for supplying alternating current to avwinding of a corresponding one of said transformers, two relays, oneconnected with the secondary of each transformer, an indicator constantly connected with a source of energy, and means controlled by said relays for at times de-energizingsaid indicator.

, 19. In combination, two circuits tuned to resonance at different frequencies, two transformers, means controlled by, each said tuned circuit for supplying alternating current to a winding of a corresponding one of said transformers, two relays, one connected with the secondary of each transformer, an indicator, ,a supply circuit for said indicator including a source of energy, and means effective when either or both of said relays are energized for' imposing upon said supp y circuit an electromotive force equal in magnitude and opposite in direction to the electromotive force of said source.

20. In combination, two 'clrcuits tuned to different frequencies, a relay controlled by each circuit and arran d to be energized only when current of t e proper frequency is being supplied to thevassociated circuit, a

first indicator arranged to be'energi zed when either of said relays is energized but de-energized when both are energized, a second indicator arranged to be energized only when both said relays are energized, a third indicator constantly connected with a source of energy, and means for de-energizing said third indicator when either of the other indicators is energized.

21. In combination, a stretch ofrailway track, means for selectively supplying said stretch with alternating current of different frequencies, a trackway signal comprising an indicator constantly connected with a sourceof ener a plurality of other indicators for sai signal, means responsive to the presence and the frequency of current in the rails of the section for selectively energizing said latter indicators, and

means for'de-energizing said first indicator when any of the remaining ind cators is energized.

22. In combination, two hot wire relays, means for selectively energizing said relays, an indicator constantly connected with asource of electromotive force, and means controlled by said relays for at times neutralizing said electromotive force.

23. In combination, two. hot wire relays, means for selectively energizing said relays, an indicator, a circuit for said-indicator including a source'of electromotive force, and means controlled by said relays for at times supplying to said circuit a sec- 7 0nd electromotive force op osite in direction and'substantially'equa in magnitude to said first electromotive force.

In testimony whereof I aflix m signature.

mas o. eao AHL. 

